As you are working on your file, you can save it
in the native Photoshop® format. The Photoshop® format retains
layers, channels, and clipping paths. Once you have completed the
file, save it again as a Photoshop® file and then do a "Save
a Copy as", in order to save it in another format such as
TIFF or EPS. When you save the file in the TIFF or EPS format, you
have to flatten your layers first which makes it harder to come back
later to edit the file. Because the flattening makes it difficult
to edit, you should always keep your original Photoshop® file
so that additional editing can be performed later. QuarkXPress
cannot import the Photoshop® format without a special XTension,
but Adobe InDesign is capable of importing the Photoshop®
format.